Hydraulic coupling



HYDRAULIC COUPLING H. SINCLAIR Fil ed Nov. 7, 1,935

Patented 19, 1937 UNITED. STATES PATENT OFFICE f Harold smfi-f il siigfffnfiinngmd Application November '1, 1935, Serial No.'4a.625 In Great BritainNovember 14, 1934 21 Claims.

The present invention relates to hydraulic couplings of the kinetic type, having a vaned impeller .member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that the impeller and runner together form a toroidal working circuit in which the workinmg liquid can circulate in the form of a vortex a- 1t is well known that the torque required to stall the runner of such a coupling while the impeller is rotated at a constant speed is of the order of 15m 20 times the normal torque load corresponding to a slip of 2 to 3 per cent.

Although such a couplihghas the useful property of cushioning the transmission of sudden shock loads and vibrations, it is of little value as a torque-limiting device in those applications where the prime mover has a substantially constantspeed characteristic, such as an alternatingcurrent motor. For example, when applied to such machinery as rock crushers', rotary welldrilling rigs, rolling mills, dredging cutters, conveyors, haulage winches and so forth, which are Y liable to be stalled by'overload, the known types of hydraulic coupling cannot serve as a load limiting device having a reasonable ratio of stalling torque to normal driving torque.

Such couplings are often employed, for example in self-propelled vehicles, to couple an engine to a change-speed gear of the kind in which the various gear ratios are engaged by the operation of friction clutches or brakes. With gears of this kind it is possible to make rapid changes from, one

- ratio to another, the frictionclutches or brakes serving to force the speeds of the driving and driven shafts ofthe gearing into the ratio of the engaged' gear. Owing to the high inertia of the vehicle, the speed of the driven shaft of the gear cannot be varied rapidly, so that a sudden gear change causes a sudden change in the speed of the driving shaftofthe gear and of the coupling runner attached thereto. Since, owing to the inertia oi the engine, the couplingin ipeller cannot change speed as rapidlyas does the coupling with a low slip, but when the torque reaches a predetermined value will permit the driven shaft to stall at a reasonable torque which may be of the order of full load torque, 1

My United States Patent No. 1,831,770 describes a hydraulic coupling of the kinetic type having an annular ring, which can be slid, by means of a pedal, into and out of .the working circuit, for the purpose of varying the torque transmission capacity of the coupling. When that arrangement is used under conditions where sudden variations in the relative speed of the impeller and runner -may occur, it is essential for the operator to time accurately the operation of thel pedal, if abnormal torque loads are to be avoided.

According to the present invention, a hydraulic coupling of the kinetic type set forth, and comprising a throttling element which is normally clear of the vortex stream 01 working liquid circulating within the hydraulic working circuit of the coupling and which can be slid into the path of this stream fonthe purpose of reducing the torque transmission capacity of the coupling, is characterized in that this throttling element is biased (for example by a spring) towards its normal position, but is adapted to be drawn automatically into the stream under the influence of a fluid pressure difierence which is set up between the ends of the throttling element in consequence of the torque transmitted by the coupling rising ,into' that circuit through an aperture in the boundarythereof for the purpose of reducing the torque transmission capacity of the coupling, the throttling element being adapted to be drawn automatically into its operative positio in said circuit under the influence of a fl pressure difference which is set up between t e spaces on opposite sides of said aperture whe the torque transmitted by the coupling rises to high value.

The specific constructions herei fter illustrated are to be considered in an illustrative rather. than in a'limiting sense, as various changes may be made within the scope of my invention as defined in the appended claims.

The invention will be further described with reference to the constructional examples shown in the accompanying diagrammatic drawing, in

which Figs. 1, 2, 3 and 6 show respectively three a1 native arrangements in sectional side elevation,

' Fig. 4 is an end elevation of a detail, viewed from the line 4-4 of Fig. 3, and

Fig. 5 shows a modification of the arrangement shown in Fig. 1.

In the arrangement shown in Fig. l the impeller 2 is fixed directly to the driving shaft I, and to the periphery of the impeller is secured a dished casing 3 which encloses the runner 4. The driven shaft 5 passes through this casing, in which it may be supported by a bearing 6; and a gland 1, which is preferably of the diaphragm type as described in my United States Patent No. 2,011,735 prevents escape of liquid between the casing and the driven shaft. To the back of the dished shell of the runner 4 is secured a saucershaped element 4' the diameter of the outer edge of which is somewhat larger than the diameter of the circular axis of the working circuit. The middle of the element 4' is provided with a boss which is fixed to the driven shaft 5, so that a chamber 8 is formed bounded at the rear by the element 4' and at the front by the radially inner part of the shell of the runner 4 and by a flanged cup-shaped pressed member 9 fixed to the inner part of the runner shellby screws ID. A short cylindrical ring valve, ll, having a diameter slightly less than the diameter of the chamber 8, is normally housed in the chamber, being mounted on a spider l2 the hub l3 of which is slidable along a rod l4 lying on the coupling axis and having its ends supported by the driving and driven coupling parts. The rod is screwed into theend of the driven shaft 5 and journalled at IS in the boss' of the impeller.

The front edge of the ring valve normally liesin an annular aperture IS in the runner shell. If the spider I2 is slid towards the impeller 2, the ring valve H projects through this aperture into the working circuit, the runner vanes being suitably slotted (as at H) to permit this movement.

A compression spring 18 disposed between the hub of the spider and an inwardly'turned flange on the inner edge of a central hole in the bottom of the cup 9, urges the ring valve towards its inoperative position.

respectively, may communicate between the chamber 8 containing the ring valve and the core space. Alternatively, as shown in Fig. 5, the

chamber which normally houses the ring valve may communicate by a port 23, withthe space I between the runner parts 4 and l and the dished casing 3, which space communicates with the V circuit by means of the gap between the radially outer parts of the impeller and the runner.

The spring I8 is just strong enough to keep the ring valve It in its inoperative position when the slip in the coupling is normal and the circulation velocity is accordingly low. When, how-' ever, the slip increases'and the circulation velocity accordingly rises, a difference is tablished between the fluid pressure in the circuit adjacent to the ring valve chamber 3,which is sufficient to draw the ring valve into the circuit.- This checks the vortex circulation of the liquid and prevents an excessive rise in torque. The

pressure difference is thought to be due mainly pressure, and consequently the overloed capacity r of the coupling, can be easily adjusted The ring valve spider l2a is fixed to a rod 24- co-axial with and slidable longitudinally of the coupling. The front end of the driven shaft 5a is counter-bored at 25 to accommodate a bellows gland one end of which is sealed to the hub l3a of the spider I24:

.and the other end of which is sealed to the driven shaft by being clamped under a hollow screw 21.

The rear end of the rod 24 passes through the counterboreand through an axial hole in the driven shaft to a'slot 28 in the driven shaft which accommodates a transverse cotter pin 29 fixed to the end of the-rod. The ends of this pin engage a collar 30 slidable on the driven shaft and urged to the rear by a spring l8a acting against a collar 3| fixed to the driven shaft by a set screw and capable of being adjusted to' various positions along the shaft to vary the setting,

of the spring.

In this construction the ring valve II is arranged similarly to the ring valve in Fig; l. The ring valve chamber 3a, however, communicates by a port 23 or series of such ports with the space between the runner parts 4a and l'a and the casing element 3a. Operation of the automatic ring valve in this coupling is the same as thathereinbefore described with reference to Fig. 1.

The bellows sealing device is particularly suitspider l2b is mounted adjacent to the impeller 2 and is fixed to a rod 24b slidably carried in a counterbore 32 in the front end of the drivenshaft 5b, the shell of the runner lb' and the core 40 member 20b being slotted in way of the spider arms, at 33 and 34 respectively, to allow the ring valve to move into its operative position, through a circumferential gap lib in the runner core guide member 2012 against the pressure of a spring llb disposed between the hub l3b of the spider and the front end of the driven shaft. The ring valve is provided with one or more longitudinal ribs 35. engaged in a recess or recesses 33 in the core guide member 20b; this arrangement prevents the spider from rubbing on the edges of the slots 33 and 34..

The arrangement shown in Figs. 3 and 4 may modified as shown in Fig. 6, the core guide member on the impeller 2 being omitted. Under normal load conditions at .low slip, the valve Hb the vortex circulation increases, with the result that a pressure difference is set up between the end of the valve nearest the boundary of the working ,circuit in th'element lb and the end a varied impeller member in the former an annularly dished shell juxtaposed to a vaned runner member of similar form, so that; said impeller and runner together form a toroidal working cir cuit. in which working liquid can circulate in the form of a vortex ring, a throttling element which is normally clear of the vortex stream of working the coupling is high.

2. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, a ring valve co-axial with,-and slidable longitudinally of the coupling, so as to be capable of obstructing the circulating vortex, and biasing means which urge said ring valve towards a position where it is clear of the path of the vortex stream, but which exert such a force that said throttling element can be drawn automatically into the path of said stream under the influencepf fluid pressure whenthe slip in the coupling is high.

3. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, a ring valve co-axial with, and slidable longitudinally of the coupling, and

biasing means which urge said ring valve intoexerted by said stream when its circulation velocity is high. I

4. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in theform of a vortex ring, said circuit having a boundary with an aperture formed therein, a throttling element which is normally clear of said circuit and which is capable of being slid into said circuit through said aperture, and biasing means which serve to urge said throttling element towards its normal inoperative position, said'throttling element being capable of being drawn automatically into its operative position into said circuit as a result of a fluid pressure difference which is set up between the spaces on opposite sides of said aperture when the torque transmitted by the coupling rises to a highvalue.

5. A hydraulic coupling of kinetic type having ing circuit in which working liquid can circulate in the form of a'vortex ring, one ofsaid shells having an aperture, a chamber formed on the back of 'said apertured shell, a throttling element which is normally accommodated in said cham- -ber and which can slide through said aperture into said circuit, biasing means which serve to urge said throttling element towards itsinoper ative position in said chamber, and a communication between said chamber and said working circuit in addition to said aperture, said communication permitting, when the slip in the coupling exceeds a predetermined value, the establishing of a fluid pressure diflerence, between the ends of said aperture, suflicient to overcome the force exerted by said biasing means.

6. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, one of said shells having an aperture, a chamber formed on the back of said apertured shell, a throttling element whichis normally accommodated in said chamber and which can slide through said aperture into said circuit, biasing means which serve to urge said throttling element towards its inoperative position in said chamber, and a duct leading from said chamber and opening into said toroidal working circuit in the neighbourhood oi the circular axis thereof, said duct permitting, when the slip in the coupling exceeds a predetermined value, the establishing of a fluid pressure diiference, between the ends of said aperture, sufiicient to overcome the force exerted by said biasing means.

'7. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal work-' ing circuit in which working liquid can circulate in the form of a vortex ring; core guide members in said circuit partly enclosing an annular space in the neighbourhood of the circular axis of said circuit, one of said shells having an aperture, a

I chamber formed on the back of said apertured shell, a'throttling element which is normally accommodated in said chamber and which can slide through said aperture into said circuit, biasing means which serve to urge said throttling element towards its inoperative position in said chamber, and a duct communicating between said chamber and said annular core space.

' 8. A hydraulic coupling of kinetic type having,

a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned ing circuit in -which working liquid can circulate in the form of a vortex ring, the shell of said runner havingan aperture, a chamber formed on the back ofsaid runner, a throttling element her and which can slide through said aperture into said circuit, biasing means which serve to -urge said throttling element towards its inoperative position in said chamberland a duct leading from said chamber and opening into said toroidal working circuit in the neighbourhood'of the circular axisthereof, said duct permitting, when the slip in'the coupling exceeds a predetermined value, the establishing of a fluid pressure difierence, between the ends of said aperture, sufiicient to overcome the force exerted by said biasing means.

9. A hydraulic coupling of kinetic type having a vanedimpelle-r member in the form of Y an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal workingv circuit in which working liquid can circulate in the form of a g runner member of similar form, so that said impeller and runner together form a toroidal workwhich is normally accommodated in said chamber formed on the back of said runner, a throttling element which is normally accommodated in said chamber and which can slide through said aperture into said circuit, biasing means which serve to urge said throttling element towards its inoperative position in said chamber, and a duct conimunicating between said chamber and said anin the form of a vortex ring, a chamber formed on the back of one of said vaned elements, a casing attached to the other of said vaned elements, a space being formed between said casing and the one of said vaned elements provided with said chamber, which chamber communicates by a port with said space, and the shell of said vaned element provided with said chamber having an aperture, a throttling element which is normally accommodated in said chamber 'and which can slide through said aperture into said circuit, and biasing means which serve to urge said throttling element towards its inoperative position in said chamber.

11. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, core guide members in said circuit partly enclosing an annular space in the neighbourhood of the circular axis of said circuit, one of said core guide members having an aperture, a throttling element normally accommodated within said annular' spacev and capable of being slid through said aperture j into said working circuit, and biasing means which urge said throttling element towards its normal ing circuit in which working liquid can circulate.

in the form of avortex ring, a ring valve which is normally accommodated in the neighbourhood of the circular axis of said working circuit'and which can be slid towards the shell of one of said vaned coupling elements for the purposeof reducing the torque transmission capacity of the coupling, and means for biasing said ring valve towards its normal inoperative position, said means permitting said ring valve to move towards saidlast-mentioned shell under the iniluence of a fluid pressure difierence which is set up between the ends of said ring valve when the torque transmitted by said coupling rises to' a high value. I 13. A hydraulic coupling of kinetic type having a varied impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring,'a throttling element which is normally clear of the vortex stream of working liquid, and which is slidable into the path of said stream for the purpose of reducing the torque transmission capacity of the coupling, driving and driven shafts on which said impeller and runner members are respectively mounted, a rod co-axial' with and slidably mounted in one of said shafts, said throttling element being mounted on said rod, and biasing means for urging said throttling element towards its normal inoperative position, but which permit said throttling element to be drawn automatically into the path of said stream under the influence oi? fluid pressure when the slip in the coupling is 14. A hydraulic coupling of kinetic type having a vaned impeller member in the form. of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, a throttling element which is normally clear of the vortex stream of working liquid, and which is slidable into the path 01' said stream for the purpose of reducing the torque transmission capacity of the coupling, spring means for biasing said throttling element towards its normal in'operative position,

but which permit said throttling element to be drawn automatically into the path of said stream under the influence of fluid pressure when the slip in the coupling is high, and an adjustable member located outside-said coupling and operable ior varying the setting of said spring means.

15. A hydraulic coupling of kinetic type having a. vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, a throttlingelement whichv is normally clear of the vortex stream of working liquid, and which is slidable into the path of said stream for the purpose of reducing the torque transmission capacity of the coupling,

driving and driven shafts on which said impeller and runner members are respectively mounted, a rod supporting said throttling element and slidably mountedin an axial bore in one of said shafts, a bellows device arranged to seal said rod with respect to the one of said shaitsin which it is mounted, an adjustable member located outside" said coupling, and spring means for biasing said throttling element towards its normal inoperati've position, said spring means being operatively connected between said rod and saidad- J'ustable member. I I,

16. A hydraulic coupling of kinetic type having a vaned impeller member in the form 01' an annularly dished shell juxtaposed to a vaned runner -member of similar form, so that said impeller and runner together form a toroidal ,working circuit in which working liquid can circulate in the chamber and said circuit at a place in said cirform of a vortex ring,-the boundary wall of said cuit remote from said aperture, said biasing means permitting said throttling element to be drawn automatically into the path of said stream under the influence of fluid pressure when the. slip in the coupling is high.

17. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, the boundary wall of said circuit having an annular aperture, a ring valve slidable into and out oi. said circuit through said aperture, biasing means for urging said ring valve out of said circuit, a chamber which accommodates said ring valve when it is out of said circult,and means communicating between said chamber and the junction in said circuit between said impeller and runner members, said biasing means permitting said throttling element to be drawn automatically into thepath of said stream under the influence of fluid pressure when the slip inthe coupling is high.

l8. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a v ring, .one of said shells having an annular aperture, a chamber formed on the back oi. said apertured shell, a ring valve normally housed in said chamber and slidable through said aperture into said circuit, biasing means for urging 1, said ring valve towards its inoperative position in said chamber, and a communication between said chamber and said working circuit in addition to said aperture, said communication permitting, when the slip in the coupling exceeds a predetermined value, the establishing of a fluid pressure diiference, between the 7 ends of said aperture, suflicient to overcome the force exerted by said biasing means.

.' 19. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner together form a toroidal working circuit in which working liquid can circulate in the form of a vortex ring, one of said shells having an annular aperture, a chamber formed on the back or said apertured shell, a ring valve norr mally housed .in said chamber and slidable through said aperture into said circuit, biasing .means for urging said ring valve towards its inoperative position in said chamber, and a duct leading from said chamber and opening into said toroidal working circuit in the neighbourhood form of a vortex ring, a throttling element which is normally clear of the vortex stream of working stream for the purpose of reducing the torque transmission capacityof the coupling, and spring means operatively connected with said throttling element and just strong enough to keep said "throttling element inits normal inoperative of the circular axis thereof, said duct permitting,

' liquid, and which is slidable into the path of said position when theslip in the coupling is low but to permit said throttling element to be drawn into said circuit under the influence oi the velocity head ofthe vortex circulation when the slip is high.

21. A hydraulic coupling of kinetic type having a vaned impeller member in the form of an annularly dished shell juxtaposed to a vaned runner member of similar form, so that said impeller and runner togethertorm a toroidal working circuit in which'working liquid can circulate in the form of a vortexlring, the boundary wall of said ring valve when it is out of said circuit, means communicating between said chamber and said circuit ata place in said circuit remote from said aperture, and spring means operatively connected with throttling element and just strong enough to keepsaid throttling element in its normal inoperative position. when the slip in the coupllng'is low but to permit said throttling element to be drawn into said circuit under the HAROLD SINCLAIR.

aperture, a chamber which-accommodates said 

